Referred to by some as a "paradigm shift," the open-source software phenomenon is having a significant impact on the information technology landscape. Although the revenue generated by open-source software does not come from the products themselves but from related hardware, software, and services, that revenue is now in the billions of dollars and growing. This issue of the journal contains 18 papers on a variety of topics related to open-source software, including Linux, Eclipse, the open-source project collaboration model, the use of open-source software within governmental institutions, and IBM activities in open-source software development.